The overall goal of the proposed program of research is to identify the visual structures (complex features) and the dynamical tuning processes (adaptation) that humans utilize in perceiving their natural visual environment while they are actively engaged with it. The key element of our program is that we consider structure and relations between structures rather than pixel-based contrast patterns to be the fundamental representational primitives of vision and we develop a methodology to identify these primitives. We will define important structures in a statistical framework as significant higher order correlations among basic local measurements of image attributes (e.g. orientation, motion, contrast). We then combine rigorous psychophysical methods with new image manipulation techniques and with static and head-mounted eye tracking systems for a systematic analysis of the image features that support the identification and recognition of real and abstract objects. We will start with studies of perception of two-dimensional stationary images by normally-sighted people and expand our work to vision of freely inspected three-dimensional natural scenes and to people with visual impairment. The direct relevance of the present work to public health comes from the transitional component of the proposal. Our research methodology developed with visually-healthy subjects will be directly applied to two visually-impaired populations with the overall goal of informing the development of image enhancement techniques, effective low cost visual aids and visual training strategies to maximize visual function in patients with glaucoma and age-related macular disease. With the combination of basic and applied visual research, we hope to establish new and efficient approaches to rehabilitation of these visual diseases. Project Narrative The overall goal of the proposed program of research is to study how healthy humans and patients with visual deficiencies perceive their visual environment, what features they utilize in the during object and scene recognition. We will investigate the perception of still and moving images using psychophysical and eye-movement measures. Understanding these fundamental issues will allow us to develop specific image enhancement and rehabilitation techniques that can form the basis of effective visual aids and interventions for the visually impaired.